The present invention relates to an improved racket frame, and more particularly relates to an improvement in construction of a racket frame head defining a face formed by a lattice work of tensioned strings.
Recent developments of racket frames cover a wide variety of types from wooden racket frames to metal racket frames to FRP racket frames. A wide variety of materials have been used for strings forming the face in the racket frame head.
Most conventional racket frames have a general construction in which a head is coupled to a grip via a yoke and has a substantially oval shape defining a face formed by a latticework of strings held in tension on the head. More specifically, the latticework is made up of two groups of strings, the first group of strings run in the longitudinal direction of the oval shape and the second group of strings run in the lateral direction of the oval shape.
In such racket frame heads, the closed construction of the head does not allow easy elastic deformation of the head towards the center of the face in response to impulsion caused by shooting balls. Thus, the impulsion caused by shooting balls is mostly incurred by the face defined by the head and elastic deformation of the face poses great mechanical load on the component strings. Since the impulsion cannot be shared by the head and is incurred by the face only, no great repulsion on balls can be expected. Due to generation of the great load on the strings, it is not possible to use high stiffness fibers such as aramid fibers and extra-high molecular compound polyethylene fibers which exhibit low energy loss.